It’s constructed from 490,000 cubic metres of rock, 32,000 cubic metres of concrete, and more than 3,000 tonnes of reinforcing steel.
110,000 cubic metres of drainage rock and 25,000 tonnes of sand were imported to the site for use in construction.
17,000 metres of drilling was needed for the waterproof grouting around the dam.
The concrete face of the dam by itself is 12,000 square metres, and it needed 4,000 cubic metres of concrete to be produced. An on-site concrete batching plant was set up to make this concrete – turning what would have been a one-hour drive for a concrete driver into just five minutes. To construct the longest concrete slab on the concrete face, the concrete slipforming had to run continuously for 50 hours!
The spillway is 165 metres long.
It has a 158-metre-long reinforced concrete channel for water to flow down when the reservoir is full. It can handle 1,058m3 per second (which is like pouring an Olympic-sized swimming pool into the chute every two seconds).
The Diversion Culvert
The diversion culvert is 165 metres long, 7 metres wide and 5.6 metres high.
It is made of 4,500 cubic metres of concrete and 815 tonnes of steel.
Inside the culvert is 160 metres of pipework.
It is designed to pass a 1-in-1,000-year-flood.
At its construction peak, there were approximately 150 predominantly local people employed onsite each day.
The estimated economic benefit in the first two years is $55 million, and between $600-$900 million over 25 years (NZIER report).
On Rough Island, Waimea Water Ltd planted 40,000 trees over a 3-year period.